I took 3rd Year Korean with Professor Chung, not beginner Korean, but I think she only teaches 1st and 2nd Year Korean now. Anyway, if you have been blessed with the opportunity to take Chung's class, DO IT. She is by far, my favorite professor, favorite teacher EVER. She's like an angel without wings, and I've never seen her angry, upset, or even peeved off; she always comes to class in a good mood, bright and bubbly, and ready to teach you all about Korean. A teacher with her patience and temperament would probably usually go into teaching pre-school kids, but the gods have blessed Columbia students by placing her here. That doesn't mean that she treats us like kids, though... She genuinely respected and cared about each and every student in her class.
You also learn a lot from her class, and she does her best to incorporate fun things (about Korean pop culture, Korean dramas, etc.) into her class so that everyone stays interested. She's always willing to answer questions, and she takes student opinions into account when teaching too!
tl;dr - Think about the kpop girl group idol member that everyone falls in love with for her adorable and lovable personality, imagine if that idol member went into teaching at the university level, and that's basically Chung.